PC PSU in series with no minimum load

[MeliorMundus]

Greetings!
Need a little help regardless PSU-s.
So i got myself four PSUs from some HP servers. They are all ATX and they all have same specs, but two of them cant start without load.
I need to put them in series so i could get 48v for another project.
Unfortunatley, they don't have seperate ground on 12 5 and 3.3 V, and can't put any load if i put them in 12V series.
I searched over internet, but there is no info on this specific issue, that I can find.
I alleready isolated PCBs from case and connected grounds spots on PCB with wires, and put diodes across 12V before putting them in series.
Any idea how to start them and not blow them? THX in advance

[madires]

Welcome to the forum! Better get a 48V PSU (look for telco surplus). No headaches with different start-up times, EMI, and other issues when putting multiple SMPSUs in series.

[MeliorMundus]

THX madires, but not an option for tonights build

[MeliorMundus]

Can i put some load between 5 and 3.3V positives to fool it to work? I checked, 12V from the fan is different ground. Can i put something betweeen 5v and fan GND?

[Gyro]

ATX PSU outputs are all ground referenced aren't they? I don't think you can put them in series.

I might be wrong of course.

[MeliorMundus]

i isolated PCB ground from earth.

[Gyro]

Ah, ok. Definitely not recommended safety wise, but I understand.